1. Field of the Invention
The invention relates to navigation systems, and more particularly to navigation systems in vehicles.
2. Related Art
Navigation systems are finding increasing use in vehicles to provide a vehicle user, the driver, with navigation instructions that help orient the driver when traveling unknown routes. In general, a navigation system includes a positioning device, which is typically based on a positioning system such as the global positioning system (GPS), for determining the vehicle's position with respect to a digital map representation. Navigation systems also typically include a processing system and suitable hardware and software to generate navigation information and the navigation instructions conveyed to the driver using the vehicle position and user input information such as a user-selected navigation route.
Navigation instructions may be presented to drivers as routes from an originating position to a destination. Navigation systems have evolved to make use of information about the geography between points and may now offer the driver options regarding the routes that may be taken between any two points. For example, a navigation system may use traffic information data that may be obtained from a Traffic Message Channel (TMC). The TMC is a publicly available digital radio data service used for broadcasting information on traffic conditions to suitable receiver devices. The navigation system may use the traffic information to instruct the driver on alternative routes that would avoid unfavorable traffic conditions.
Navigation systems may also provide a user with alternative routes that include features that may be of interest to drivers. For example, points having scenic views, or businesses such as restaurants, gas stations, ATM machines or other facilities that may be of interest to a driver may be provided on a map database. The navigation system may make use of this information provided on map databases and provide alternative routes that include such points of driver interest based on the driver's preferences.
The possible routes between points may include features or characteristics that are of interest to the driver and that may not be included in the map database. For example, a driver of a sports vehicle may prefer to take a longer route to a destination if it has curves, hills, or other characteristics that make a drive fun or exhilarating in a sports vehicle. Characteristics such as the curviness of the road, or the hilliness of the road, are not part of a map database. Such subjective characteristics may vary according to the type of vehicle being driven, or the personal preferences of the driver. Routes based on their “sportiness” are therefore not identified by navigation systems.
There exists a need for navigation systems to provide optional routes to a destination based on the “sportiness” of the routes.